Fasting causes competition for nutrients between mother and fetus. The rate of maternal protein degradation may be lower in pregnancy in order to protect maternal stores while supplying the fetus. This rate will be measured by constant maternal infusion of 1-13C leucine with application of steady state isotope dilution methods & will be compared in pregnancy & post-partum. Disturbance of the control of protein degradation may be responsible for altered fetal growth rate in gestational diabetes & preeclampsia.